Your guide to the cast of characters in Christopher Nolan’s Dunkirk

One of the most eagerly anticipated films of the summer, the great Christopher Nolan’s WWII epic Dunkirk promises to turn war movie convention on its head. Of course, we’d expect nothing less from the visionary director of Interstellar, Inception and the Dark Knight trilogy. And as usual, he’s paid close attention to the casting, combining familiar faces from his previous films with some real surprises. So while we puzzle over why Michael Caine doesn’t appear to be involved this time, here’s our run-down of some of the key cast members.

Fionn Whitehead – Tommy

Who? Don't worry, you'll only have come across 19-year-old Londoner Whitehead if you caught the ITV mini-series Him. Nolan knew that he needed a fresh young face to play his aptly named main protagonist Tommy, in order to underline the youth and inexperience of many of those who found themselves thrown in to the pivotal evacuation. It took months of auditions to find the actor who forms the film’s emotional core as a young British private through whose eyes we experience the chaos, danger and bravery of Operation Dynamo. A delighted Nolan has compared his young star with the young Tom Courtenay.

Harry Styles – Alex

You might be forgiven for thinking that the presence of former One Direction star Harry Styles qualifies as stunt casting, designed to bring his huge teenage audience flocking to the film. But Nolan doesn’t do that sort of thing and has stoutly defended his decision. Styles was recruited after hundreds of young men were auditioned, with Nolan remarking simply that he “had it”. Mind you, the hunky popster certainly seems to have been put through the wringer in his feature debut. The 'Dunkirk' trailer shows his character, Alex, pitched into the briny after his rescue vessel is torpedoed in a spectacular enemy attack. It's unclear how much longer he'll survive…

Tom Hardy – Farrier

Nolan brilliantly interweaves stories from land, sea and air. It's in the air that we meet Tom Hardy's Spitfire ace, who's charged with protecting the evacuation from a relentless Luftwaffe assault - only to become a target himself. Hardy is one of a number of cast members who could be described as Nolan regulars, having made his career breakthrough in Inception. He also contributed on of the screen's most memorable villains when he played sinister, terrifying Bane The Dark Knight Rises.

Cillian Murphy

Marking his fifth collaboration with Christopher Nolan, the Peaky Blinders star plays a soldier who's hurled from a ship only to be miraculously rescued by one of the fleet of vessels sailing across the Channel by plucky Brit civilians to assist in the evacuation. Alas, this takes him straight back into the jaws of death.

Kenneth Branagh ­– Commander Bolton

Evacuating 400,000 trapped and, in many cases, shell-shocked soldiers from the beaches of Dunkirk under intense enemy fire, with the assistance of a fleet of non-military volunteers, is one hell of a task. So itæs a relief to find Kenneth Branagh in charge of the logistics, with a little help from subordinate James D’Arcy. Branagh brings his full military bearing to the role and no doubt savours the opportunity to triumph over the Nazis, having failed to assassinate Hitler as Major General Henning von Tresckow in Bryan Singer’s true-life WWII drama, Valkyrie.

Mark Rylance – Dawcett

Operation Dynamo was extraordinary for many reasons, none more so than the fleet of some 700 small private boats that sailed from Ramsgate to help evacuate the trapped soldiers. That’s where the phrase “Dunkirk spirit” comes from, in recognition of their captains’ bravery and patriotism. Oscar-winning Bridge of Spies star – and voice of the BFG, lest we forget – Mark Rylance plays one of their number.

With young Barry Keoghan aboard his ‘little ship’, he’s but one of many risking their lives to help save the day. Not everyone is persuaded that this is a good idea – especially the military. As Cillian Murphy’s rescued solider exclaims: “You're weekend sailors not the bloody navy. You should be at home!”